One Button Bob

Another NinjaDoodle favourite of mine.
In this one you control Bob who's on a mission to find a treasure or something. You control Bob with the mousebutton which functionality changes on every new gamescreen.

It's frustrating as hell but quite fun.

Play it here:
http://www.ninjadoodle.com/one-button-bob/

And if you like it, there's a similar one here that's even harder:
http://www.ninjadoodle.com/one-button-arthur/